The subject matter disclosed herein relates to an electric machine and, more particularly, to an electric machine rotor with rotor vent and axial slot fluid communication.
In electric machines, a stator is normally formed to define a bore in which a rotor is rotatably supported. The stator includes conductive elements provided as stator windings. The rotor includes a squirrel cage or an amortisseur winding such that rotation of the rotor within the bore while an excitation current is applied to the stator windings can generate current in the conductive elements, which are disposed to extend through the stator when the electric machine is run in a generator mode. By contrast, current applied to such conductive elements can interact with the squirrel cage or amortisseur winding and thereby cause the rotor to rotate in a motor mode.
During operation of the electric machine in either the generator or motor mode, a large amount of heat can be generated in various elements. This heat can lead to damage to motor components, the stator or the rotor but primarily to stator winding insulation if the heat is not removed or the heated elements are not otherwise cooled. One way to remove heat and to cool the various elements in an electric machine is to form cooling paths through the stator and/or the rotor by which coolant, such as ambient air, is directed through or across heat generating parts, such as the conductive elements. Cooling path formation can be difficult, however, because it can often lead to negative magnetic circuit impacts, which reduce the performance of the electric machine. Therefore, placement, sizing and selection of geometry of the cooling paths is of utmost importance.